Metal-coated substrates, interposers, and methods for production thereof

Abstract

Substrates may be metallized by introducing a seed layer upon a base substrate, mechanically polishing the seed layer, and forming a metal layer upon the seed layer after mechanical polishing. The base substrate may comprise a ceramic, such as silicon nitride or aluminum nitride, a polymer, silicon, metal, or glass. The seed layer optionally may be rendered electrically conductive by mechanical polishing of an initially non-conductive seed layer. The metal layer may be formed by depositing a metal nanoparticle composition upon the seed layer after mechanical polishing and consolidating metal nanoparticles therein, such as through a hot pressing operation. The metal nanoparticle composition may contain one or more additives that facilitate CTE matching of the metal layer to the base substrate.

What is claimed is: 
     
         1 . A metallized substrate comprising:
 a base substrate;   a seed layer directly adhered to the base substrate, the seed layer being mechanically polished to form a polished seed layer and comprising a non-conductive matrix material and a plurality of metal particles, optionally wherein the polished seed layer is electrically conductive; and   a metal layer formed upon at least a portion of the polished seed layer.   
     
     
         2 . The metallized substrate of  claim 1 , wherein the base substrate comprises a ceramic, a polymer, silicon, or glass. 
     
     
         3 . The metallized substrate of  claim 2 , wherein the base substrate comprises a ceramic selected from the group consisting of aluminum nitride, silicon nitride, indium tin oxide, and any combination thereof. 
     
     
         4 . The metallized substrate of  claim 1 , wherein the non-conductive matrix material comprises a material formed from a liquid glass binder, a polymer adhesive, or any combination thereof. 
     
     
         5 . The metallized substrate of  claim 1 , wherein the base substrate comprises glass or a ceramic, and the non-conductive matrix material comprises a material formed from a liquid glass binder. 
     
     
         6 . The metallized substrate of  claim 1 , wherein the base substrate comprises a ceramic or a polymer, and the non-conductive matrix material comprises a polymer adhesive. 
     
     
         7 . The metallized substrate of  claim 1 , wherein the metal particles comprise copper particles having a size of 1 to 5 microns. 
     
     
         8 . The metallized substrate of  claim 7 , wherein the metal layer comprises copper. 
     
     
         9 . The metallized substrate of  claim 1 , wherein the metal layer is CTE-matched to the base substrate. 
     
     
         10 . The metallized substrate of  claim 1 , wherein the metal layer comprises a continuous metallization layer or one or more metal traces. 
     
     
         11 . The metallized substrate of  claim 1 , wherein the seed layer has a thickness ranging from about 500 nm to about 50 microns. 
     
     
         12 . The metallized substrate of  claim 1 , wherein the metal layer has a thickness ranging from about 100 microns to about 2000 microns. 
     
     
         13 . An interposer comprising the metallized substrate of  claim 1 , wherein the base substrate comprises aluminum nitride or silicon nitride, and the non-conductive matrix material comprises a material formed from a liquid glass binder or a polymer adhesive. 
     
     
         14 . A process comprising:
 providing a base substrate;   applying a seed layer precursor to the base substrate;
 wherein the seed layer precursor comprises a non-conductive matrix material and a plurality of metal particles; 
   curing the seed layer precursor on the base substrate to form a non-conductive seed layer adhered to the base substrate;   mechanically polishing the non-conductive seed layer to form a polished seed layer, optionally wherein the polished seed layer is electrically conductive; and   forming a metal layer upon at least a portion of the polished seed layer.   
     
     
         15 . The method of  claim 14 , wherein forming the metal layer upon at least a portion of the polished seed layer comprises:
 applying a metal nanoparticle composition on the polished seed layer; and   consolidating a plurality of metal nanoparticles within the metal nanoparticle composition.   
     
     
         16 . The method of  claim 15 , wherein consolidating the plurality of metal nanoparticles takes place by a hot pressing operation. 
     
     
         17 . The method of  claim 14 , wherein the base substrate comprises a ceramic, a polymer, silicon, or glass. 
     
     
         18 . The method of  claim 17 , wherein the base substrate comprises a ceramic selected from the group consisting of aluminum nitride, silicon nitride, indium tin oxide, and any combination thereof. 
     
     
         19 . The method of  claim 14 , wherein the non-conductive matrix material comprises a material formed from a liquid glass binder, a polymer adhesive, or any combination thereof. 
     
     
         20 . The method of  claim 14 , wherein the metal particles comprise copper particles having a size of 1 to 5 microns. 
     
     
         21 . The method of  claim 20 , wherein the metal layer comprises copper. 
     
     
         22 . The method of  claim 14 , wherein the metal layer comprises a continuous metallization layer or one or more conductive traces. 
     
     
         23 . The method of  claim 22 , wherein the metal layer comprises one or more conductive traces formed by selective etching of the continuous metallization layer. 
     
     
         24 . The method of  claim 22 , wherein the metal layer comprises one or more conductive traces formed by selectively depositing a metal nanoparticle composition on the polished seed layer. 
     
     
         25 . The method of  claim 14 , wherein the metal particles comprise micron-size metal particles, metal nanoparticles, or any combination thereof. 
     
     
         26 . The metallized substrate of  claim 11 , wherein the seed layer has a thickness of 5 microns to 30 microns.